1. Field of the Invention
The present invention relates generally to optical waveguides and more particularly to whispering gallery waveguides for infrared light.
2. Discussion of the Background
Although fiber optics waveguide have been widely used for transmitting visible light, they are not completely successful at transmitting infrared radiation. In particular, fiber optic waveguides undergo large losses at the infrared frequencies. Since infrared waveguides are necessary in places where it is not desirable to use rotatable mirrors and articulated arms, other forms of waveguides have been developed.
One such infrared waveguide is shown in U.S. Pat. No. 4,194,808. In this type of waveguide, a highly polished metal surface, such as copper, is used to transmit surface waves of infrared radiation. Although this type of apparatus works very well, problems still arise in the easy fabrication of this device and in maintaining the quality of the transmission.
Although copper does act as a good transmitter of these waves, it does not provide sufficient rigidity for easy formation and maintenance of the waveguide. Accordingly, copper by itself is not a perfect solution.
Other materials such as nickel have been utilized to form the waveguide which have greater rigidity and allow the waveguide to be self-supporting. However, nickel has a relatively low thermal conductivity and as a result has other problems. Specifically, this type of guide cannot withstand very high laser power and heats up rather quickly to high temperatures even at moderate laser power.